1. Technical Field
Photoresist monomers, polymers thereof and photoresist compositions containing the same are disclosed. In particular, photoresist monomers suitable for a photolithography process using DUV (deep ultraviolet) light sources, particularly VUV (vacuum ultraviolet: 157 nm) in fabricating a minute circuit for a high integration semiconductor device, photoresist polymers thereof, photoresist compositions containing the same, and preparation processes are also disclosed.
2. Description of the Related Art
In general, a useful photoresist for ArF and VUV has a variety of desired characteristics, such as low light absorbance at the wavelength of 193 nm and 157 nm, excellent etching resistance, and excellent adhesiveness to a wafer. In addition, a photoresist should be easily developable in a commercially readily available developing solution, such as 2.38 wt % and 2.6 wt % aqueous tetramethylammonium hydroxide (TMAH) solution.
Recently, much research has been conducted on resins having a high transparency at the wavelength of 248 nm and 193 nm and dry etching resistance similar to novolac resin. However, most of the photoresists are not suitable for VUV due to their poor transmittance at 157 nm wavelength.
Photoresists containing fluorine have good transmittance at these wavelengths. Unfortunately, most photoresists containing fluorine with a polyethylene, polystyrene or polyacrylate polymer backbone have weak etching resistance, low solubility in an aqueous TMAH solution and poor adhesiveness to the silicon wafer. In addition, these photoresists are difficult to mass-produce and are expensive.
On the other hand, photoresists containing fluorine with alicyclic polymer or maleicanhydride-norbonene polymer backbone have good adhesiveness to the silicon wafer, low light absorbance at the wavelength of 157 nm and excellent etching resistance compared to photoresists with polyacrylate backbone.
Accordingly, novel photoresist monomers, polymers thereof and photoresist compositions containing the same that can be used for a light sources such as ArF (193 nm) and VUV (157 nm) are disclosed.
A process for forming a photoresist pattern using the photoresist compositions described above and a semiconductor element produced by using the process described above are also disclosed.